How do you deal with litter box smell?

My mother-in-law lives with us, and we got a cat that she takes care of. She keeps the litter box in her room. Unfortunately, the smell is almost intolerable to me (not to her). Recently she bought one of those $300 automated cat litter boxes saying that she wouldn’t have to use as much litter and that she’d only have to change the litter out once a month. The smell is now so bad I’m nauseated. I think she should use more litter and change out the waste every day. How do you cat owners deal with your litter boxes? Any suggestions on how I can convince her to be more aggressive in dealing with the waste?